Variable speed reducer



April 14, 1959 H. E. MORRIS I I ,8

VARIABLE SPEED REDUCER Filed May 16, 1956 4 Sheets-Sheet 1 'fllfa'rvey.

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April 14, 1959 H. EfMoRRls 6 VARIABLE SPEED REDUCER I Filed ma 16, 1956 I g, 4 Sheets-Sheet 3 INVENTO 24 rd] 0727s.: BY W April 14,1959 H. E. MORRIS 2,881,626

' VARIABLE SPEED REDUCER Filed May 16, 1956 4 Sheets-Sheet 4 INVE TOR.

BY I

United States Patent i 2,881,626 VARIABLE SPEED REDUCER f Howard E. Morris, Chicago, Ill.

Application May 16, 1956, Serial No. 585,215

'10 Claims. (Cl. 74-342 My invention relates generally to a variable speed re-I ducer and more particularly to a novel gear train arrangement for use in a variable speed reducer.

--The popular trend of employing miniature battery powered electric motors in mechanical toys has presented aproblem of providing economical means for reducing the speed of the motor to a desired rate without, of:

course, resorting to the use of rheostats ,or the like. in

the motor circuit. Such motors are mass produced. at v relatively low cost and usually operate at speeds of 40005000 r.p.m. It is of course understood that speed requirements in difierent types of toys may vary ,requiring in each case, a different gear train arrangement. This necessitates special consideration for each different application with a special gear train arrangement for each case. Thus, while the motor may be mass produced in large quantities and the same type of motor may be employed in a great many types of toys the same has-not been true of the gear train arrangements heretofore used, each of such arrangements requiring individual tooling and different fabrication with a consequent higher cost of production.

. Accordingly it is an object of my invention to provide a speed reducer adapted for attachment to a motor housing and embodying a novel gear train arrangement utilizing identical interchangeable gears which may be arranged in operative engagement according to a predetermined order to provide a series of speed reductions of different values within a certain range.

Another object of my invention is the provision of a device of the foregoing character which may be economically mass produced and in which a single basic structure may be employed in a great variety of applications, it being required only to utilize one or more of a seriesof interchangeable gears with such structure to obtain a desired reduction in speed. 1

A. further object of my invention is the provision of a device of the foregoing character which lends itself to fabrication by moulding from plastic materials or by die casting.

Other and further objects and advantages of my invention will become apparent when considered in connection with the following description and the accompanying drawing in which Fig. l is a vertical cross sectional view illustrating an embodiment of my invention. a

Fig. 2 is an elevational view taken on line 2.2 of Fig. 1 with the cover removed.

Fig. .3 is a more or less diagrammatic view showing the gear train arrangement illustrated in Fig. 2.

, 4 is a perspective view partly in cross section of the body structure showing the relationship of the gear supporting studs.

Fig. 5 is a view similar to Fig. 4 and showing the gear train supported on the studs.

Figs 6 and 7 are respectively front and side elevational viewsv of an interchangeable gear.

', Fig. 8 is a view taken on line 8-8 of Fig. 1, and,

2,881,628 Patented Apr. 14, 1959 ice Fig. 9 is a view taken on line 9-9 of Fig. 1. Referring to the drawings the numeral indicates generally an electric motor which except for certain structural features incorporated in the end housing member 16 as will be presently described is of conventional con-' struction. The said end housing member 16 includes the usual axial bearing in which is journaled one end of the.

a series of rectangular apertures 21 spacedly arranged and adapted to receive cooperating'hook elements 22 attached to a speed reducer assembly 23, the said hook elements serving housing.

The speed reducer assembly 23 comprises a generally cylindrical housing 24 having a circulartransverse wall 26. and a skirt portion 27 eccentric to the housing 24, as seen clearly in Fig. 8. Extending rearwardly from the wall 26 are a plurality of fingers 28 each having at its end a hook element 22 adapted to engage against a respective embossed portion 29 adjacent each of the apertures 21 in the end housing member 16. When the parts are assembled the fingers 28 are caused to flex outwardly in passing through the apertures 21. When the hook elements 22 are passed completely through the apertures the fingers 28 assume the position illustrated in Fig. 1 with the skirt portion 27 engaging against an annular seat 31 in the end housing member 16. The v parts thus are held securely in assembled relation.

As seen clearly in Figs. 1 and 8 the transverse wall 26 within the area circumscribed by the skirt portion 27 is oliset to provide a circular well (Fig. 4) with a portion of the wall 26a cut away to provide a clearance opening 33 in which is received a portion of the driving pinion 19. A post 34 extends from the center of the well 32, the post having a base portion 35 of increased diameter to afford a thrust bearing surface for the first gear element 36 rotatably supported on the post 34. Said first gear element 36 includes a relatively thin spur gear 37 adapted to'operatively engage with the pinion 19 and an integral K gears 52 and 53 each having different numbers of teeth.

portions of the respective posts are so arranged-that coopspur gear 38 of substantially increased axial length. The

gear 38 extends beyond the surface of the wall 26 as seen clearly in Figs. 1 and 5.

Disposed centrally of the wall 26 is a hollow boss 39' affording a bearing for rotatably supporting an outlet includes a lower portion which has a diameter greater than 'the upper portion to afford a thrust bearing surface for supporting a' gear element 51 (Figs. 6 and 7) adapted to be rotatably carried on the upper post portion and hereinafter to be described. I

Referring particularly to 4 it will be seen that the lower enlarged portions ofv the posts 42-48 are of diiferent heights with the post 42 immediately adjacent the post 34 being the shortest and the remaining posts in a counterclockwise direction increasing progressively in height in the manner of a helix with the post 48 having the greatest height. Each of these posts is adapted to rotatably support a gear element 51 illustrated in detail in Figs. 6 and 7. All gear elements 51 are identical and may be molded as a unit to include two integral spur For convenience the respective gear elements and components thereof will be identified by suflixes a, b, c, d, e, f and g. For example, gear 52 in the present embodiment has 8 teeth while gear 53 has 12 teeth. The enlarged eratinggears. of successive gear elements .operate inprogressively higher planes with the smaller gear of one gear element being in operative engagement with the larger gear ofya succeeding .gear element. Forfexample gear-52a1on post 42 is adapted to .beoperatively engaged with. gear 5312 on post 43, the saidgears 52a and 53b being disposed substantiallydn the same plane. Gear 52b on post-43 correspondingly is'adapted tobe operatively engagedwith gear 53c on post 44, thesaid last mentioned gears'similarlybeing in the same plane. The same relationship holds true for each of the cooperating succeeding gear; elements. It will be apparent that in each .step through the train, of gears a reduction inspeed is effected. Mounted on the outputshaft .41 for rotation therewith is a; gear54. As will be. seen by reference to Fig. 2 the said gear has a greater number of teeth than any of the gears 52 with which the gear 54 is adapted to cooperate in the embodiment'illustrated the gear 54-.has l8.teeth. As viewed in Fig. 3 the pitch diameter of gear 54 is tangent to the projected pitch diameter of each of the respective gears'52 such that if the gear 54 were shifted axially into planar alinement respectively with each of the gears 52 and gear 38 each of said gears would be separatelyoperatively engaged with gear.54.

,Where-a maximum gear reduction is desired a full com plement of gear elements 51 will be employed as illustrated in Figs. 2, 3 and 5. Under such conditions utilizing all the gears illustrated there is obtained a speed reduction ratio of 1:013 between the. motor shaft 18 and theoutput; shaft 41.- In the last describedcondition the gear 54 is;disposed in planar alinement-and in operative engagement with gear 52g supported on post 48. If a lesser speed reduction ratio isv desired for example 1:019v the gear element lg-on post 48 is eliminated and the gear 54. is positioned on shaft 41 so that it willbe in planar alinement and inoperative engagement withgear .521 on post 47. It will be understood that it is contemplated to provide shaft 41, with longitudinal splines and press fit the gear 54thereon'at the desired axial position so that it is disposed in planar alinement with a particular gear 52. Thus, by placing-the gear 54 at different longitudinal positions on the shaft 41 the said gear may be caused to cooperate with different gears 52 to provide different speed reductions,'itbe ing understood that all gear elements 51 following in a counterclockwisedirection, as viewed in Fig. 2, the gear element meshed with the gear 54 will be eliminated, since such gear elements do not function.- For example, utilizing the gear train combinations below iniQate the following gear reduction ratios between the motor; shaft 18 andthe output shaft 41 may be obtained.

Geartrain combination: Gearreduction ratio Gears 38 and 5 4 12222 Gears 38,f5 3a, 52 a and 54 1:148 Gears 38, 53a, 52a, 5317,.52b and 54 1:098

.. in which is received the corresponding end of arespective interchangeable gear elements with said basic structure to obtain a desired speed reduction within the range of the device.

It will be understood that various changes and modifications may be made from the foregoing without depart" g from thespi rit and scope of the appended claims.

- I claim:

1. A device of the character described comprising an input shaft having a gear mounted thereon, anoutput shaft, a gear mounted on said output shaft, a series-of ;similar rotatably mounted gear elements spacedly arranged-in a helix coaxial with the output shaft, each of said gear elements consisting of two gearsionehaving a greater number of teeth than the other and a gear of one gear element being adapted to mesh with'a noncorresponding gear of an adjacent element,- the pitch v a gearthereon, a trainof similar rotatably supported gear diameters of corresponding gears of said series of elements being equal and all projectedpitch diameter-slicing tangentto the pitch diameter of said output gear, sl'aid inputshaft gear being in operative engagement with one s of said series-of gear elements, said output gear being adapted'to be selectively positioned axially of said output shaftfor selective cooperative engagement with one of said corresponding gears for varying the speed reduction ratioibetween said input and said output shafts. A

2. ,A device of the character described comprising a base, an output shaft rotatably supported in said base, "a plurality of posts supported on said base and spacedly arranged radially equidistant from the axis of said output shaft, a gear supported on said output shaft, a plurality of similar gear elements, one rotatablysupported on each oflsaid posts, each gear element comprising two gears injuxtaposition with one of said gears having a greater number of teeth than the other of said gears andwith non-corresponding gears of adjacent gear elements being in operative engagement, the projected pitch diameters of all of the gears of .one series of corresponding gearsbeing equal and tangent to the pitch diameter of said shaft gear, said last mentioned gear being adapted to be selectively positioned axially of said shaft for selectively cooperative engagement with one ofthe gears-of said one series for varying the speed between said input and output shafts. I

3.. Ina device of the character described, an output shaft, .a gear carried on said shaft, an input shaft, a gear carried on said shaft, a series of posts spacedly arranged radiallyequi-distant from the axis of said output shaft, a

first series offidentical gears, each rotatably supported on a p.o st, a secondseries of gears each rotatably supporte'd on a post, a gear of said first series 'being in operative engagementwith an adjacent gear of said second seriesfthe K gears on each of said posts being operatively connected,

the projected pitch diameters of all of the gears intlsaid first series being equal and tangent to the pitch'diamelter of said .output shaft gear, said last mentioned gear being adapted to beselectively positioned axially of said shaft for selective cooperative engagement with one ofthe gears of said firstseries for varying the speed between saidiiiput and said output shafts.

4'.; In.a..device of the character described comprising an input shaft having a gear thereon, an output sjh alftihaving elements, each of said gear-elements consisting oftwo gears with'one of said gears having a larger number of teeth than the other and arranged in cooperative engagement so that the gear with the smaller number of teeth will cooperatively engage an adjacent gear of a larger number of teeth, said output gear adapted to be selectively positioned axially of said output shaft for coopera tive engagement with any one of the gears having the smaller number of teeth for varying the speed ratio between said input and said output shafts.

5. In a device of the character described comprising an input shaft having a gear thereon, an output shaft having a gear thereon, a train of similar rotatably supported gear elements operated by said input gear, each of said gear elements consisting of two gears with one of said gears having a larger number of teeth than the other gear, said gear elements being arranged in progressively higher planes with the small gear of one gear element in operative engagement with the larger gear of a succeeding gear element, said output gear adapted to be selectively positioned axially of said output shaft in planar alinement with any one of the gears having the smaller number of teeth for cooperative engagement therewith for varying the ratio between said input and said output shafts.

6. In a device of the character described comprising a housing having a plurality of posts of progressively increasing heights, a gear element rotatably supported on each of said posts, each said gear element consisting of two gears with one of said gears haivng a larger number of teeth than the other gear, said gear elements being arranged in progressively higher planes on said posts with the gear with the smaller number of teeth of one gear element in operative engagement with the gear having a larger number of teeth of a succeeding gear element, an input gear for operating said chain of gear elements, an output gear mounted on an output shaft and operated by said chain of gear elements, said output gear adapted to be selectively positioned axially of said output shaft in planar alinement with any one of the gears having the smaller number of teeth for cooperative engagement therewith for varying the ratio between said input and said output shafts.

7. In a device of the character described comprising a housing having a plurality of posts of progressively increasing heights, a gear element rotatably supported on each of said posts, each said gear element consisting of two gears with one of said gears having a larger number of teeth than the other gear, said gear elements being arranged in progressively higher palnes on said posts with the gear with the smaller number of teeth of one gear element in operative engagement with the gear having a larger number of teeth of a succeeding gear element, an input gear for operating said chain of gear elements, an output gear mounted on an output shaft and operated 'by said chain of gear elements, said output gear adapted to be selectively positioned axially of said output shaft in planar alinement with any one of the gears having the smaller number of teeth for cooperative engagement therewith for varying the ratio between said input and said output shaft, a closure member for said housing having bosses of varying lengths with bores for receiving said posts, the ends of said bosses affording a thrust bearing for said gear elements.

8. In a device of the character described comprising a housing having a plurality of posts provided with thrust bearings of progressively increasing heights, a gear element rotatably supported on said post adjacent said thrust bearing so that said gear elements are arranged in progressively higher planes, each said gear element consisting of two gears with one of said gears having a larger number of teeth than the other gear and the gear with the smaller number of teeth 5 1 operative engagement with the gear having a larger number of teeth of a succeeding gear element, an input gear for operating said gear elements, an output gear mounted on an output shaft and operated by said gear elements, said output gear adapted to be selectively positioned axially of said output shaft in planar alinement with any one of the gears having the smaller number of teeth for operative engagement therewith for varying the ratio between said input and said output gears.

9. In a device of the character described comprising a housing having a plurality of posts provided with thrust bearings of progressively increasing heights, a gear element rotatably supported on said post adjacent said thrust hearing so that said gear elements are arranged in progressively higher planes, each said gear element consisting of two gears with one of said gears having a larger number of teeth than the other gear and the gear with the smaller number of teeth in operative engagement with the gear having a larger number of teeth of a succeeding gear element, an input gear for operating said gear elements, an output gear mounted on an output shaft and operated by said gear elements, said output gear adapted to be selectively positioned axially of said output shaft in planar alinement with any one of the gears having the smaller number of teeth for operative engagement therewith for varying the ratio between said input and said output gears, and an end closure member for said housing having thrust bearings of progressively varying heights in inverse order to the thrust 'bearings of said posts, said last mentioned thrust bearings supporting said gear elements against removal.

10. In a device of the character described comprising a housing having a plurality of posts provided with thrust bearings of progressively increasing heights, a selective number of gear elements mounted on certain of said posts dependent upon the gear reduction desired, said gear elements rotatably supported on said posts adjacent said thrust bearings so that said gear elements are arranged in progressively higher planes, each said gear element consisting of two gears with one of said gears having a larger number of teeth than the other gear and the gear with the smaller number of teeth in operative engagement with the gear having a larger number of teeth of a succeeding gear element, an input gear for operating said gear elements, an output shaft, an output gear mounted on said output shaft, said output gear adapted to be selectively positioned axially of said output shaft in planar alinement with the highest positioned gear having the smallest number of teeth for operative engagement therewith for varying the ratio between said input and output gears.

References Cited in the file of this patent UNITED STATES PATENTS 1,990,036 Kratz et al Feb. 5, 1935 2,349,064 Weaver May 16, 1944 2,436,746 Drought Feb. 24, 1948 2,622,454 Boehm Dec. 23, 1952 2,704,464 Lautenbach et al Mar. 22, 1955 2,735,309 Tew Feb. 21, 1956 2,775,904 Edwards Jan. 1, 1957 FOREIGN PATENTS 272,057 Switzerland Mar. 16, 1951 

